The Big One: the problem with 11 There's a big difference between 'a necessary being' and 'God'. God is usually given many more properties than 'has to exist'.

The problem with 2. It's not absolutely clear that all things had to happen before now. It's implicitly (explicitly?) assumed that there would be times where there is something existing. Obviously, this is one of those times. Maybe the nothing existing time is in the future.

And another problem with 2. If there are infinite possibilities, it is possible that we will never cover all the possibilities, even given a infinite amount of time.

The problem with 3. Aquinas seems to be assuming that contingent beings have finite life spans. This doesn't seem to follow. In fact, it's kindov weird to say that 'Nothing Can Come From Nothing' (7), but then allow for something to become nothing.